Surgery for Pediatric Bladder Anomalies Clinical Presentation

Bladder diverticula

Bladder diverticula are herniations of the bladder mucosa through bladder wall musculature (detrusor muscle). ^[8] Diverticular size can vary greatly, with some attaining a size equal to or greater than the volume of the bladder. Diverticula can be wide- or narrow-mouthed, as dictated by the size of the musculature (detrusor) defect. The size of diverticular openings has functional implications because narrow-mouthed diverticula often empty poorly. Stasis of urine within diverticula can also lead to stone formation or epithelial dysplasia. ^[9]

Depending on the size and location, bladder diverticula may cause ureteral obstruction, bladder outlet obstruction, or vesicoureteral reflux (VUR). Ureteral obstruction is unusual, occurring in approximately 5% of children with bladder diverticulum. Bladder outlet obstruction is rare. However, VUR is more common, affecting 8-13% of patients. ^[10]

Bladder diverticula most commonly occur lateral and superior to the ureteral orifices. They may also occur at the dome of the bladder, particularly in such disorders as bladder outlet obstruction (ie, posterior urethral valves) or Eagle-Barrett syndrome (prune belly syndrome).

Bladder diverticula may be congenital or acquired; in children, most are congenital. ^{[11, 12]} Congenital deficiency or weakness in the Waldeyer fascial sheath has been implicated as a cause. Congenital diverticula tend to be solitary and are located at the junction of the bladder trigone and detrusor. This location, close to the insertion of the ureter into the bladder, is important because large diverticula can impinge on or distort the ureteral orifices. Surgical excision of these diverticula must therefore be undertaken with care to avoid ureteral injury. ^[11]

Acquired diverticula are the result of obstruction, infections, or iatrogenic causes. They tend to be multiple and occur in trabeculated bladders. Examples of loci of obstruction include posterior urethral valves (PUVs), anterior urethral valves, urethral strictures, neuropathic bladder, and external sphincter dyssynergy. An example of iatrogenic diverticula is herniation of the bladder mucosa through the ureteral hiatus after antireflux surgery because of inadequate closure of the ureteral hiatus.

Many diverticula that are related to obstruction spontaneously resolve after relief or correction of the obstruction. In some cases, the diverticula that occur in response to obstruction serve a beneficial function by acting as pressure pop-off mechanism, protecting the kidney and ureters from high pressures.

Some children with diverticula have voiding dysfunction on urodynamic testing. Whether the voiding dysfunction leads to the formation of diverticula or the presence of diverticula leads to voiding dysfunction is unclear. ^[13]

Urachal anomalies

A urachal sinus derives from a persistently patent urachus. The sinus drains to the umbilicus, and this drainage often is the result of episodic infections of the sinus, resulting in the appearance of purulent drainage at the umbilicus. Children may present with periumbilical tenderness, a wet umbilicus, or granulation tissue at the level of the umbilicus. In many cases, these children have undergone multiple silver nitrate cauterizations under the mistaken notion that this is simply granulation tissue after severance of the remnant umbilical cord.

A urachal cyst is a fluid-filled structure occurring in between the two obliterated ends of the urachus (ie, the umbilicus and bladder dome). Most occur in the distal third of the urachus. In infancy, such cysts are rarely symptomatic, but they are detected with increasing frequency as an incidental finding during bladder ultrasonography (US) in children undergoing evaluation for other reasons (eg, antenatal hydronephrosis or urinary tract infections [UTIs]). More commonly, the urachal cyst is detected in early childhood or adolescence.

Symptoms of a urachal cyst are generally related to infection and the resultant inflammation and include suprapubic mass, fever, pain, and bladder or irritative voiding symptoms. Staphylococcus aureus is the most common bacterial organism. The peritoneum alone separates the cyst from the intra-abdominal cavity; thus, the inflammatory process may involve the adjacent intra-abdominal contents, resulting in abdominal pain. Death from intra-abdominal rupture has been reported.

A patent urachus is a communication from the umbilicus to the bladder. Infants present with continuous or intermittent drainage from the umbilicus. Crying, straining, voiding, or the prone position may accentuate intermittent drainage. The tract may become inflamed, resulting in tenderness, periumbilical swelling, and serosanguineous or purulent discharge.

A patent urachus may also be associated with bladder outlet obstruction, such as PUVs. Correction of the obstruction may result in the spontaneous resolution of the patent urachus. However, if the patent urachus persists beyond several months after relief of the obstruction, it should be surgically corrected.

A vesicourachal diverticulum is an outpouching at the apex of the bladder that results from incomplete closure of the proximal urachus. Most patients are asymptomatic because the diverticula drain well with bladder emptying. Often, vesicourachal diverticula are incidentally discovered during evaluation for other reasons. Rarely, they become large and empty poorly, resulting in recurrent UTI or stone formation. ^[14]

Bladder ears

Bladder ears are lateral protrusions of the bladder through the internal inguinal ring and into the inguinal canal. In infants, the bladder assumes a more abdominal position, which places it in close proximity to the internal inguinal ring. With growth, the pelvis becomes more developed, and the bladder assumes a more pelvic position. Therefore, this anomaly is rarely observed in adults.

Bladder ears are often observed during voiding cystourethrography (VCUG) or intravenous pyelography (IVP), when the bladder is filled to capacity. Bladder ears have also been seen on computed tomography (CT) body imaging. Knowledge of this entity is important to surgeons during inguinal herniorrhaphy because occasional reports have been made of partial or near-total cystectomy performed under the mistaken notion that this was a large hernia sac.

Bladder agenesis

Bladder agenesis is rare and generally incompatible with life. Fewer than 20 cases have been reported in live births, all of them in females, presumably because females have less outlet resistance than males do and thus have preservation of renal function. Ureters may enter into the urethra, vagina, Gartner duct cyst (female), prostatic urethra, rectum, or the patent urachus.

Most often, associated hydroureteronephrosis and renal dysplasia (variable) are present. Other associated anomalies include neurologic, orthopedic, hindgut, and other urogenital anomalies, such as renal agenesis and absence of the prostate, vagina, seminal vesicles, epididymis, or penis.

Megacystis

Megacystis is an enlarged bladder, believed to be secondary to overfilling of the fetal bladder during development. It is often discovered postnatally as the evaluation of antenatal hydronephrosis is completed. Febrile UTI is the other common presentation.

This condition is associated with massive high-grade VUR, which may also be the etiology of megacystis. In the presence of massive reflux, a large percentage of the voiding bladder volume is refluxed into the upper tracts. This causes constant recycling of the urine between the bladder and ureters, resulting in progressive dilation of both. ^[15]

Megacystis can be observed in other conditions, such as PUVs, Ehlers-Danlos syndrome, ^[16] urethral diverticulum, microcolon hypoperistalsis syndrome, ^[17] sacral meningomyelocele, sacrococcygeal teratoma, and pelvic neuroblastoma.

Bladder duplication

Bladder duplication is rare. ^{[2, 3]} It can be complete or partial, with complete duplication more common than incomplete duplication. ^{[18, 19]} The two halves of the bladder are on either side of the midline, with the corresponding ipsilateral ureter draining each bladder half.

Associated anomalies occur with much greater frequency in complete bladder duplication, including duplication of the penis, vagina, uterus, lumbar vertebrae, and hindgut. In addition, fistulas may be present between the rectum, vagina, and urethra. With complete bladder duplication, two urethras exist; with incomplete bladder duplication, the bladder joins distally into a single common urethra.

Bladder septation

Bladder septation anomalies are rare. Fibromuscular or mucosa septations divide the bladder into equal or unequal portions. Septations may be complete or incomplete. The functioning of the associated renal units depends on the adequacy of upper-tract drainage.

For many of the bladder anomalies, no overt physical findings are observed. They are elucidated after radiologic imaging for such things as a history of antenatal hydronephrosis or UTI. The usual physical findings relative to each of the anomalies are as follows:

• Bladder diverticula - None
• Urachal sinus - Intermittent drainage from umbilicus (may be serous or serosanguineous)
• Urachal cyst - None (with an infected cyst, physical findings include infraumbilical or suprapubic mass with tenderness or erythema of overlying skin)
• Patent urachus - Intermittent umbilical drainage (may be serum or urine)
• Vesicourachal diverticulum - None
• Bladder ears - None
• Bladder agenesis - None (most of the physical findings pertain to various associated anomalies)
• Megacystis - None
• Bladder duplication - None (in complete bladder duplication, two urethral openings may be identified)
• Bladder septation - None